29. By NEMO. (A military message).
A O T O I N E H T C T O T L I I A W G E L P R V L R I I R I U A D E O
W L R R R L C M E O N P E P T A V T S O H O E E N L S N P S S B Y T S
L R O P D R G E T S S T S Y A W N E.
30. By PICCOLA. (Hostilities?)
T A M L R I T E D W E E D H H N P W O S W R S H C N O I E D O H I L T
C S T N I W A A R C D H H D A I E T P T R L R O W A S E E T A K F P W
G M A T X E K A H D P I L E O F H W G I N H A K S F S S A A A H E H N
D H H E H.
31. By AMSCO. (The "AMSCO" Cipher).
N W L E L N T L C S L W D L Y L N S O O I D F I N R U C H A L N D C B
S I D E A I T E T I K S T B E E O U T J A T I L I A C O R E A Y E E G A O.
32. By PICCOLA. (Can you recover this nice long keyword from the numbers?)
Y K I E T N T H H E X I A E N U B A K E E W S C S I H T N L N E N E A
K I E O B O L I E E A M C I F T I N A H S K A N I D L G S O E E I T T
S W H L L E U A D H F S H A B E O E N O A N O S C P H S N O D H T X R
N H R E A.
33. By PICCOLA. (An easy Myszkowski. Probable words: SOLVE, CIPHER, COLUMN).
V I N S R C F E A E O O H S E F H L E T F H U N S T N C L T S L C I A
E E S H R H S I R E T T M T S E T E P D T S O I N M R T T H T L O L R U B E.
34. By PICCOLA. (Nothing like a bit of "philosophy" - oyeah?)
E L O S W E A H X P N N T R N H L W I E G E I G E A E Q A G L E A R R
Q L O N K E S Q L O R N X A R S P X S E E A E I P A G L R E P R Y M T
H N K S E I X X A Y.
35. By PICCOLA. (Not so easy; still, it's just another columnar).
H R O T E T E T E H I W E O T T D A O D K G DT C E R A I W O S Y N H
Y R H T W.

CHAPTER VII
General Methods — Multiple Anagramming, Etc.

In the past few chapters, we have been looking at all of the general methods for decryptment of transpositions. We have seen the use of factoring, which determines, for the geometric cipher, what key-lengths are possible, and, for the irregular one, what key-lengths are not. Vowel-distribution has enabled us, in some cases, to determine the length of major units, or has assisted in the restoration of minor units to their original intact groups. Anagramming has been seen throughout: the matching of letters and columns with or without the application of language statistics.

So far, we have been materially assisted by advance knowledge as to what the cipher is. Where the type is unknown, and cannot be promptly identified, and assuming, of course, that the decryptor has no probable words, transpositions, taken as a whole, present confusing problems in the very multiplicity of their possibilities. General Givierge, in his Cours de cryptographie, remarks of this case that novices, as a rule, display a tendency to recoil from the cryptogram as if uncertain “which end to pick it up by.” He adds that the best advice he can give is to pick it up somewhere and do something, rather than be satisfied to sit all day long and admire the cryptogram!

As to how a type may sometimes be identified, the difference between the regular and irregular types is ordinarily suggested by the number of letters contained in the cryptograms. Irregular types, intended for practical purposes, are nearly always seen in complete five-letter groups, where the geometric cipher usually results in a broken group at the end of its cryptogram. This, of course, is never mandatory upon the encipherer; it merely happens because the only persons making use of such ciphers are those who do not realize the advisability of doing otherwise.

Among the irregular types, a columnar formation can usually be spotted by the “bunching” of vowels at intervals throughout the cryptogram. Then, too, we are still to see those cases in which the exact type of the cipher may not become apparent until after solution is well started.

It is usually well, when a new system is encountered, to analyze it and find out what the transposition finally does to the letters. This can be done by preparing actual cryptograms in which the plaintext letters are serially numbered; or, if the question of vowel-distribution is not involved, by using the serial numbers without the letters, as suggested in . Many ciphers, of course, will not require even this amount of analysis, even though their type, accurately speaking, is irregular. For example, the one shown as Fig. 48, whether or not its rectangle is to be completed, is merely another route, so that once having seen it, we might try to follow this route again. But the student who cares to give this cipher his careful consideration must notice that its longer cryptograms would be full of reversed plaintext segments; that these would grow longer and longer with a constant rate of increase, and would always alternate with incoherent segments which, in their turn, would grow shorter and shorter; also that these incoherent segments, if set up as columns, would show plaintext.

The complete-unit cipher, generally speaking, can hardly present any real complexities. Consider, for instance, the following variation on a Nihilist encipherment, which was proposed by Geo. C. Lamb, the author of [Chapter X]: The key-length, to begin with, must be divisible by 3, but this is not used for writing-in. The plaintext is written into its block, not in straight order, but following a route which begins in the upper left corner and goes forward for the first three letters, drops down to the second line and runs backward for the next three letters, drops to the third line to run forward for another three, and so on back and forth until the first three columns have been filled with trigrams written alternately forward and backward. It then moves over to the second three columns, beginning this time at the bottom and “snaking” upward to the top. For the third three columns it moves downward again, and so on until the square block has been filled. After this very devious primary transposition, the unit is taken off by means of the key, on the Nihilist principle of transposing both columns and rows with the same key.